The GX transfer cases are easier to replace just the actuator seals since they are a manual H-L set up. The trick is to time the actuator when disassembling, which I am not 100% sure how to do, but you do not need to split the transfer case to do so. I have friends that still work at Lexus, so I can get more info if you need it. The 4runner transfer cases HAVE to be disassembled in order to replace the actuator seals since they are electrically operated both 2-4 (V6) and H-L (V6 and V8), and in my experience, doing it in the vehicle without removing the entire transfer case is FAR more simple.

I'm not sure I understand this very well. The GX Tcase is an full time 4X4 Tcase which is what the V8 Runners have. So, I wouldn't call them a "manual" Tcase. I'd call the V6 Runner Tcases a "manual" tcase since they have part time rear wd ability.

Oops. I had my information wrong. The GX transfer cases are AWD, but the H-L shifter is a manual shifter instead of a switch on the dash like the 4runners. The V6 4runners are a "part-time" transfer case meaning they have a "2WD" setting also. So, the GX transfer case actuator only controls the center diff lock, and only has one shaft going into the transfer case, whereas the 4runners have 2 shafts and there is no way to disassemble these without splitting the transfer case to do so.

Ahhh, gotcha. So, the V8 black actuator box only has a single shaft going into the Tcase? Interesting.

Only on the GX's. ALL 4runners have 2 shafts.

Wow, I sure could have used this thread 3 days ago.....

My '06 Sport has been shifting kind of slowly for a while but I hadn't realized how badly until a trip this week. I wanted to creep up a really rough dirt road leading to a campsite so I tried to get my rig into 4Lo. It first switched to 4Hi no problem and I drove a few yards then stopped, put it in neutral and tried to go into 4Lo. The 4Lo dash light flashed for a good 30 seconds but never went steady. Reading the little card on the visor said to basically "try again" if the shift didn't succeed. So, I ran the dash switch back and forth a few times hoping it would lock in.

With no luck I put it back into 4Hi and let off the brake....the truck crept forward in Low range????? Uh oh....that can't be good. I stopped, back to neutral and cycled the switch a few times with the same result. This time going all the way back to 2Hi. Woo Hoo....the 4Hi light went out so all is well, right?? Not so much.

I had my friend crouch down and look under the rig. The front shaft wasn't turning but it was certainly still in low range. Now I'm screwed!!! I was in the middle of nowhere in SC and needed to get home (10hr drive) the next day. Luckily I had just enough signal to get onto the forums here with my phone.

I spent hours scouring threads other than this one, many showing the guts of the actuator, wiring diagrams, and lots of other info but nothing that really answered my question. I tried all the tapping, swerving, shifting advice posed in other threads with no success. I pulled the battery for about 30 minutes hoping that the 4wd computer was just "confused" and that this might reset it. No luck there either.

In an act of sheer desperation because I had some experience with the innards of a tcase (installed 4:1 gear kit and 2Lo shifter in a Sami years ago) I knew I should be able to shift out of low range manually if I could only get to the rods. While laying on my back in a parking lot with the front up on a curb I pulled the guts out of the actuator, breaking several parts in my haste and generally rendering it destroyed. I finally got the gears out and the case removed then moved the Hi/Lo rod by had. Woo Hoo.....high range again.

I zip-tied the two rods together and prayed this would hold together on the ride home. Today I greased up the rods and reinstalled the actuator box. The t-case had puked a few ounces of oil on the ride home so I topped it off too.

So now I have a very, very 2WD 4runner. I was sick of the Hi/Lo/Lock lights flashing like mad on the dash so I just disconnected the 4wd computer behind the glove box. Of course that made the ECU really upset so there goes the traction/stability control....oh well.

Now....most of you are probably shaking your heads at my bonehead move. Few more than myself though. This is going to be a pretty costly mistake. I'm hunting e-bay and elsewhere for either a good V6 actuator or possibly a complete used tcase and actuator.

Why is there a difference between the V6 and V8 actuators?? Both do exactly the same thing, right? The exception must be an additional limit switch in the V6 model that tells the computer to engage/disengage the front diff (ADD).

When I finally get my hands on some replacement parts is there a better way to keep this from happening again? There seemed to be very little grease inside the actuator itself. I've read several threads about people drowning the assembly but mine was squeaky clean inside. I'm not 100% sure the actuator was "bad" before I broke it. Now I'm home and both motors turn just fine when connected to a battery (I guess I have spares). Does the front actuator use the same motor??

This has been extremely helpful, especially the pages from the FSM. I've pulled the transfer case/actuator and splitting this weekend. My breather tubes were brittle and fell apart when I pulled the case so I'll be replacing them and also installing the transfer case gasket overhaul kit and actuator o-rings. Did you have any probs with your transfer case/tranny breather tubes?


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Whats the purpose of the breather tubes?

Also, everyone doesn't need to split the case to fix the O'ring. Just separate the actuator black box from the tcase and slap some toyota/lexus gasket sealer in there after you cleaned out the area with brake cleaner. Its basically a liquid version of a gasket. These applications are also similar to those used for gas appliances instead of using traditonal old teflon tape.

It will save you lots of time and money if you just do it this way. A fifteen minute job is better than a 4-8 hour job to seal a leak. Genius idea if you've asked me.

Can you really get that sealant into the gap around the shift rods without totally removing the actuator housing? That seems to be the holy grail of 4th gen tcases is to repair the actuator (or even removing it from the shift rods) then getting everything back together and shifting properly, leak or no leak.

I believe it's to keep water out if you find yourself in so deep. But the answer could be more exotic.

Let me know how that holds up over the long term. For now, I'd rather do a 8 hr job once and do it right than a 15 minute quick fix that's going to cost me more time and headache down the road. Squirting some FIPG or RTV in there is not a permanent fix, but a bandaid like Blue Devil.


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I drove 3,000 miles already. I have yet to see a leak on it. Will let you know if it does leak.


Thats what the mechanic said. take the screws off the actuator and pull it back as far as the rods let you go and clean it out and slap the sealant onto there. This is the holy grail to fix it. whether it is a temporary or permanent fix. I can say it is working for now. I rather not waste half a day trying to change an Oring and 2 seals. (which i still have but never end up using them. )

Holy grail is overselling it... it's temporary fix with potential to hold up a long while. At best you stop the leak, at worst you pull too much and pull the rods out of alignment in the actuator (had one come in another shop tried to fix that way.)

No holy grails here. Busted her open yesterday. The quick fix wouldn't have worked. Well, once you use Blue Devil, you can kinda consider all seals trashed.



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Well, after my bout of stupidity my truck is finally back together and functional. I learned a lot along the way, most of them very hard lessons.

I picked up an AISIN branded actuator (the OEM manufacturer) off Amazon for $500. It was described as for the V8 only but everything I could find here and on some of the Toyota parts sites indicated they are the same part for both. The only difference in this new unit and the old one is the inspection cover. There's not one on the Amazon unit so you can't check the timing of the diff lock shift rod from the outside.

Here's the list of truly stupid things I did that cost me lots of time but were still educational/interesting.

First of all, instead of cracking the T-case as the manual and many posts here recommend I was determined to do this repair/replacement from the outside. In that regard I was successful with one HUGE caveat....I had to pull the T-case. I figured out the timing on the new unit and dismantled/reassembled it numerous times and got all excited about putting it back together while laying on my back under the truck. I forgot about one key thing....gravity. Trying to keep greasy gears and axles in place within a single tooth while getting everything reassembled proved to be nearly impossible (at least for me).

I also had to mod the actuator box a bit. The difference between the 2-4 rod being all the way in and the diff-lock rod all the way out is about 19mm. That doesn't give quite enough clearance to get the top layer motor plate in/out of the case. I ended up notching some of the thin plastic with the dremel. If I were a little trickier and had thought of this earlier I think it would be feasible to rig up a power supply on the individual motors and monitor the index switch with a meter. That would have taken me even more tinkering and time though.

Lastly, in my haste and a bit of frustration I ended up tearing one of the oil seals....DOH. So, thanks to the forum I ordered some replacements from Colonial seal. I also took the dremel to the shoulder area of the shift rods to take off the sharp edge that had torn the seals. A little dremel work and some polishing with an old 2000 grit belt brought the whole seal area to a nearly mirror finish. We'll see how well that holds oil with time.

Luckily, I only had the t-case out and back in a single time but I cracked the actuator box open nearly a dozen times trying to get the timing right with it on the case. Half of those were "operator error" by not paying attention to the front diff actuator. Going from 2Hi to 4Hi involves moving the shift rod from all the way in, through the diff-lock position, to the fully out or "unlocked 4wheel drive" position. The last thing the 4wd computer does is lock the front diff. Only then does it give you the solid green 4Hi dash light. On a couple of my attempts I could hear the t-case shift, then the front actuator, but the lights kept flashing. I thought I'd messed up the t-case until I finally crawled under and twisted the front driveshaft and "click" the diff fully engaged....Woo Hoo green light!!

The best advice I can give is "do it according to the book." If you get in a position where you've got a gunked up motor and you end up disassembling the actuator I can probably give you a hand with the timing and getting it back together, especially if you're willing to open the T-case.

Also.....pulling the tcase isn't too bad. Just don't let the wife operate the jack and almost drop it on you. The only way I was getting mine back in solo was by building a little cradle with some scrap wood and screwing that to the foot of my floor jack. Luckily the balancer weight on the t-case ends up acting like a "foot" and keeping it almost in the right orientation. There's also one of the bolts on the bottom coming from the transmission side that's wedged up against a mount. That one was a bit of a pain to remove/reinstall.

Overall, I'm setting my phone for a monthly reminder to shift into 4lo somewhere for a few minutes and hoping I never have to deal with this again....and that the t-case doesn't leak.